Answer:
D. His improvements allowed the steam engine to run more efficiently on oil instead of coal.
Cities developed professional firefighting and police forces.
The correct answer to this question is: 1 writers who worked to reform aspects of society
Muckrackers were socially conscious journalists who worked to expose the worst aspects of society.
The<span> Maastricht Treaty created the EU.
Answer: C)</span><span> Maastricht Treaty</span>
